As one of the thermochemical water splitting hydrogen production cycles, which could be operated at the lower temperature below 1200 K, we investigated the feasibility of the cyclic operation of Ispra Mark 2 cycle with the addition of . The cycle is theoretically composed of three reaction steps; (1) 1st step(), (2) 2nd step() and (3) 3rd step(). From the TPR tests, the temperature ranges for production in 1st step and production in 2nd step were and , respectively. In system, the formation of molten products due to the reaction between manganese oxides and NaOH were greatly decreased with the addition of . In addition, the results of a cyclic test were discussed with the viewpoint of production amounts and the feasibility of the process improvement.

The purpose of this paper was to investigate the reforming characteristics and optimum operating condition of the plasmatron assisted reforming reaction for the hydrogen-rich gas production. Also, in order to increase the hydrogen production and the methane conversion rate, parametric screening studies were conducted, in which there were the variations of the flow ratio, flow ratio, vapor flow ratio, mixing flow ratio and catalyst addition in reactor. High temperature plasma flame was generated by air and arc discharge. The air flow rate and input electric power were fixed 5.1 l/min and 6.4 kW, respectively. When the flow ratio was 38.5%, the production of hydrogen was maximized and optimal methane conversion rate was 99.2%. Under these optimal conditions, the following synthesis gas concentrations were determined: , 45.4%; CO, 6.9%; , 1.5%; and , 1.1%. The ratio was 6.6, hydrogen yield was 78.8% and energy conversion rate was 63.6%.

Effect of precipitation and heat-treatment on hydrogenase which was extracted from the cytoplasmic fraction of the phototrophic purple sulfur bacterium Thiocapsa roseopersicina NCIB 8347 was studied. Crude enzyme extract was prepared by centrifugation(, ) after sonication of cells grown under photosynthetic condition for 96 hrs. Various conditions of precipitation and heat-treatment were examined and the effect of protein concentration was analyzed by SDS-electrophoresis between the treatments. Optimum conditions for precipitation and heat-treatment for evolution hydrogenase activity were 40-60% saturation and for 20 min, respectively, which exhibited the specific hydrogenase activity of 0.78 U/mg-protein. Specific hydrogenase activity was decreased to 31.6% when the heat-treatment at increased from 20 min to 5 hrs.

Two mesophilic trickling bed bioreactors filled with two different types of media, hydrophilic- and hydrophobic-cubes, were designed and conducted for hydrogen production under the anaerobic fermentation of sucrose. Each bioreactor consisted of the column packed with polymeric cubes and inoculated with heat-treated sludge obtained from anaerobic digestion tank. A defined medium containing sucrose was fed by the different hydraulic retention time(HRT), and recycle rate. Hydrogen concentrations in gas-phase were constant, averaging 40% of biogas throughout the operation. Hydrogen production rate was increased till of bioreactor when influent sucrose concentrations and recycle rates were varied. At the same time, the hydrogen production rate with hydrophobic media application was higher than its hydrophilic media application. No methane was detected when the reactor was under a normal operation. The major fermentation by-products in the liquid effluent of the both trickling biofilters were acetate, butyrate and lactate. In order to run in the long term operation of both reactor filled with hydrophilic and hydrophobic media, biofilm accumulation on hydrophilic media and biogas produced should be controlled through some process such as periodical backwashing or gas-purging. Four sample were collected from each reactor on the opposite hydrogen production rate, and their bacterial communities were compared by terminal restriction fragment length polymorphism (T-RFLP) analysis of PCR products generated using bacterial 16s rRNA gene primers (8f and 926r). It was expressed a marked difference in bacterial communities of both reactors. The trickling bed bioreactor with hydrophobic media demonstrates the feasibility of the process to produce hydrogen gas. A likely application of this reactor technology can be hydrogen gas recovery from pre-treatment of high carbohydrate-containing wastewaters.

Mg and Mg-based alloys are promising hydrogen storage alloys for renewable clean energy applications. It is a lightweight and low cost material with high hydrogen storage capacity. However, commercial applications of the Mg hydride are currently hindered by its high absorption/desorption temperature, and very slow reaction kinetics. In this work, we aim to study the absorption properties of the -5mass% Nb composite prepared by mechanical alloying under hydrogen. The absorption capacity of the sample is found to be about 3.0 wt.% at T=573 K and P=1.0 MPa. The absorption characteristics observed have been compared with those of the prepared .

Iodine-sulfur(IS) hydrogenation production process consists of three sections, which are so called a Bunsen reaction section, a HI decomposition section and a decomposition section as a closed cycle. For highly efficient operation of a Bunsen reaction section, we investigated the phase separation characteristics of system into two liquid phases(-rich phase and -rich phase) in the high temperature ranges, mainly from 353 to 393 K, and in the molar ratio of . The desired results for the minimization of impurities in each phase were obtained in conditions with the higher temperature and the higher molar composition. On the basis of the distribution of to each phase, it is appeared that the affinity between and was more superior to that between and .

The plate reformer consisting of combustion chamber and reforming chamber for 25 kW MCFC stack has been operated and computational fluid dynamics was applied to estimate reactions and thermal fluid behavior in the reformer. The methane air 2-stage reaction was assumed in the combustion chamber, and three step steam reforming reactions were included in the calculation. Flow uniformity, reaction rate and species distribution, and temperature distribution were analyzed. In particular, temperature distribution was compared with the measurements to show good agreement in the combustion chamber, however, inappropriate agreement in the reformer chamber.

The characteristics of hydrogen-oxygen mixture gas generation stack was experimentally studied in terms of efficiency. For this purpose, the mixture gas generation stack was fabricated by connecting 7 cells in series following the Tero Ranta report. In order to avoid the instrument inaccuracy, all measuring equipments were re-tested and calibrated by Korea Laboratory Accreditation Scheme (KOLAS) certified laboratories. Since the amount of produced gas is most crucial in determining the efficiency, two gas collecting methods such as bottle trap method and wet gas meter method were adopted. From the experimental results, it was found that both KOH fume and steam evaporated along with hydrogen-oxygen mixture gas, and these by-product gases could cause the misestimation of the stack efficiency. The current, voltage, and energy efficiencies of the hydrogen-oxygen mixture gas generation stack was evaluated based upon the stack efficiency calculation method summarized in this work.

In order to improve the activation properties of the type hydrogen storage alloys for Ni-MH battery, the alloy surface was modified by employing high energy ball milling. The alloy powder was ball milled for various period by using the high energy ball mill. As the ball milling time increased, activation of the type composite powder electrodes were enhanced regardless of additives. When the ball milling time was small discharge capacities of the type composite powder electrodes increased with the milling time. On the other hand for large milling time it decreased with increasing milling time. The maximum discharge capacity was obtained by ball milling for 3-4 min.

Sepiolite was selected as a mineral carbonation candidate ore for carbon dioxide sequestration. Carbonation salt formation from alkaline earth metal ingredient needs to dehydroxylation of sepiolite at high temperature. An evident dehydroxylation was observed over and the variations of sepiolite characteristics after high temperature treatment was synthetically evaluated. Remarkable weight loss were measured after high temperature thermochemical reaction then crystallographic and spectroscopic changes were analyzed. The resulted alkaline earth metal oxides could explained by dehydroxylation based on thermochemical reaction.

In this study, activated carbon(ACs) have been modified by nitric acid and heat-treatment. The surface and structure properties of ACs were determined by BET surface area, FT-IR pH and acid/base value. The changes in pore structure and surface properties of these modified ACs were correlated with natural gas adsorption which measured by volumetric apparatus at and . The pore textural properties of activated carbon was also characterized by nitrogen adsorption at 77 K. Specific surface area and micropore volume of them were calculated by Langmuir equation and Horvath-Kawazoe method, and chemical properties of surface were measured by FT-IR and titration of acid and base solutions. Pore texture of activated carbons after treatments were not significantly changed. Total acidity increased and basicity of samples decreased. however the basicity increased with heat treatment. The methane adsorption of ACs become different depending on the acid/base value of samples.

Solid polymer electrolyte(SPE) membrane with electrodes embedded on both faces offer unique possibilities for the electrochemical cells like water electrolyzer with fuel cell. The Nafion 117 membrane was used as the SPE, and and as the electrocatalysts and reducing agent, respectively. The 'impregnation-reduction(I-R) method' has been investigated as a tool for the preparation of electrocatalysts for water electrolyzer by varying the concentration of reducing agent and reduction time at fixed concentration of platinum salt, 5 mmol/L. Pt-SPE electrocatalysts prepared by non-equilibrium I-R method showed the lowest cell voltage of 2.17 V at reduction time, 90 min and with concentration of reducing agent 0.8 mol/L and the cell voltage with those by equilibrium I-R method was 2.42 V at reduction time, 60 min and with concentration of reducing agent 0.8 mol/L. The cell voltage were obtained at a current density and . In water electrolysis, hydrogen production efficiency by Pt-SPE electrocatalyst is 68.2% in case of non-equilibrium I-R method and 61.2% at equilibrium I-R method.

Porous Co-P catalysts electroplated on Cu in chloride based solution with an addition of and glycine were developed for hydrogen generation from alkaline solution. The microstructures of the Co-P catalysts and their hydrogen generation properties were analyzed as a function of cathodic current density and plating time during the electrodeposition. Amorphous Co-P electrodeposits with porous structure was formed on Cu at cathodic current density of , and showed very high hydrogen generation rate in alkaline solution due to an increase in the surface area of the catalyst as well as the catalytic activity. The Co-P catalyst, which was obtained at cathodic current density of for 5 min, exhibited the best hydrogen generation rate of 2290 ml/min.g-catalyst in 1 wt. % NaOH+10 wt. % solution at .

In the production of hydrogen from various sources like cracking of LPG, LNG, Crude oil, or alkaline water electrolysis, the things that we keep in mind is the entrapment of unexpected impurities in the stream of produced . If it is true that we are not able to produce 100% pure , then subsequent procedure is the elimination of the impurities and the determination of the concentrations of each constituents in stream. By the way, each country has different constituents in its fuels and unavoidablely it was cost/economy debates between coutries. Thus, in this paper, our goal is to provide current international issues for hydrogen production.

This paper deals with the national competitiveness of hydrogen energy. The effectiveness of investments for hydrogen energy R&D and constructions of hydrogen energy infrastructures can be evaluated by the national competitiveness of hydrogen energy, and it is evaluated by an AHP(analytic hierarchy process) method. The evaluation indices of the national competitiveness are selected as the technical level, the number of researchers, the investments for R&D, and the infrastructure of hydrogen energy. Similarly, the technical level is divided into the number of published papers, the number of foreign patents, and the number of published proceeding papers. The evaluation indices of the technical level and the number of researchers were investigated by database searches. It appears that South Korea locates the sixth position in the world. The results of our study suggest that South Korea is relatively competitive in the technical level and the number of researchers. However, our country needs the long-term and well-focused R&D, and the expansion of infrastructures to enhance the national competitiveness of hydrogen energy in the future.